Fuse-plug



F. H. KAISER.

FUSE PLUG.

APPLiCATlON FILED JAN.17, 1919.

Patented Oct. 26, 1920.

[IZVGIZtOf F H Kaiser UNITED STATES PATENT OFFICE.

FRANK H. KAISER, or BUFFALO, NEW YoRK, ASSIGNOR T0 cARoLA G. KAISER, or

' BUFFALO, NEW YORK.

FUSE-PLUG.

Patented Oct. 26, 1920.

Original application filed March 2 6, 1918, Serial No. 224,814. Divided and this application filed January 17, 1919. Serial No. 271,736.

To allwhom it may concern.

Be it known that I, FRANK H..KAISER, a citizen of the United States, residing at Buffalo, in the county of Erie and State of New York, have invented certain new and useful Improvements in Fuse-Plugs, of which the following is aspecification.

This application is a division of an application filed by me March 26, 1918, Serial No. 224,814, the object of thepresent invention being to provide novel means to automatically indicate when a plug has been blown so that a blown plug may be readily detected even among many others of its kind without the necessity of testing each plug.

In the accompanying drawings Figure 1 is a vertical longitudinal section through a fuse plug constructed in accordance with the present invention;

Fig. 2 is a similar view taken in a plane substantially at a right angle to the plane of Fig. l; I

Fig. 3 is a detail perspective view of the indicating device, and

Fig. 4 is a detail perspective view of the indicator tape.

The body 1 of the plug is constructed of porcelain or other non-conducting material and is provided between its ends with an exterior substantially cylindrical circumscribing enlargement 2, one end of the plug being open and the opposite end closed and the said enlargement being located nearer the open end. The wall of the body is increased in thicknessinteriorly at one side, as indicated by the reference numeral 5, there by providing a longitudinal fiat face 6 extending from the closed end of the plug body to a point near the open end thereof. A metallic disk 7 is seated in the lower or closed end of the body and has a portion of its edge out segmentally so as to fit against the flat face 6 and thereby serve as a nut to be engaged by the binding screw 10 which is inserted through the closed end of the body and the head 11 of which forms the center contact. The fuse wire 17 has one end looped about the shank of the binding screw 10 and held firmly between the head of the screw and the closed end of the plug body and the said wire is carried through registering openings in the end of the plug body and in the disk 7 so as to extend longitudinally of the interior of the body, as shown and as will be readily understood. The body is provided with a longitudinal passage 18 extending through the enlargement 2 and the thickened wall 5 and merging into an exterior longitudinal groove 19 formed upon the outer surface of the body below the said enlargement. The usual me tallic shell 22 constituting a rim terminal or contact is fitted upon the exterior of the body and its upper portion extends over the groove 19, as shown, while an anchor 21 consisting of a metallic strip of any desired formation has one end through the passage 18 and into the groove 19, the extremity of the anchor resting in the said groove 19 being crimped, as shown in Fig. 1, whereby it will be secured by the shell 22 and form a good electrical contact therewith without the use of solder. anchor 21 is also provided with a portion extending across the interior of the plug body and resting on the outer end of the thickened wall 5 and in the said portion of the anchor is mounted a binding screw 32 about the shank of which the outer end of the fuse wire 17 is wrapped. Vhen the screw is turned home the end of the fuse wire will be securely clamped between the head of the screw and the anchor. The open end of the fuse plug body 1 is closed by means of a metallic cap 34 which, for a purpose to be presently explained, is provided centrally with an opening 35, the wall of the cap being screw threaded, as indicated by the numeral 36, so as to adapt the cap to be removably fitted onto the upper end portion of the said body, or in other words, that portion which extends beyond the upper side of the enlargement 2. A relatively thick and stout disk of asbestos or other suitable material, indicated by the numeral 37, is disposed against the upper or open end of the body 1 and, when the cap 34 is in place, is housed within the said cap. This disk 37 completely closes the said open end of the plug body, and mounted upon the outer face of the said disk is a shell or cap 38 having a filling 39 of an explosive powder such, for example, as gun powder. A fine wire 40 is fitted at one end through the disk 37 with its said end extending into the filling 39 and the other end of this wire is coiled or wrapped, as at 41, about the fuse wire at a point approximately midway be- The inserted tween the ends thereof. A thin disk as is disposed within the closed end of the cap 34 and closes the opening 35 and this disk is preferably formed of asbestos although any other suitable material may be employed, the material of the disk being capable, however, of being more or less readily torn. The numeral 43 indicates a strip of asbestos or other suitable material which is preferably colored red and is secured at "one end, in any suitable manner as indicated by the numeral 44-, to the outer face of the disk, the

free end of this strip extending 'over the cap 38 and between the said cap and the disk a2 at a point directly opposite the opening 35 in the cap 3%. It will be understood that prior to actual fusing of the fuse wire 17, the wire will become heated. Due to the fineness of the wire 40, this wire will be heated to redness due to the heat from the fuse wire and, therefore, the powder 39 within the cap 38 will be ignited and the filling will explode causing the end of the strip at?) to be blown through the thin disk 42 and out through the opening 35 where it will be readily visible. While I have found the signal device above described to be highly eiiicient in its operation, nevertheless it will be understood that various other means may be employed for similarly giving visible signal when the fuse is blown.

In order to provide for escape of the gases and heated air resulting from fusing of the wire 17, and at the same time providing against discharge of flame from the fuse plug which would be liable {to cause fire, the enlarged portion 2 of the wall of the body of the plug is formed with vent passages 45 of which there may be any desired number and which passages preferably are curved radially and downwardly so as to discharge through the under face of the enlargement.

It will be understood thatthe disks 37 and 42 being of asbestos or similar material, are of insulating character and are also fireproof. Therefore, there is no likelihood of current being transmitted to the cap 34, nor is there likelihood of flame being discharged through the open end of the plug body from the are produced at the time of'fus ing of the wire 17.

Having thus described the invention, what is claimed as new is:

1. In a fuse plug, a body having an open end, a'fuse'wire mounted within the body,

a cap fitted to the open end of the body and having an opening therein, a disk fitted to the open end of the body and housed within the cap, an explosive charge carried by the disk, a heat conducting wire leading at one end through the disk and into the charge and at its other end connected with the fuse wire, and an indicator element comprising a strip held at one end and having its free end located between the 013611111'g in the cap and the said charge whereby whenthe disk, a heat conducting wire leading at one end through the disk and into the charge and at its other end connected with the fuse wire, an indicator element comprising a strip held at one end and having its free end located between the opening in the cap and the saidcharge whereby when the charge is exploded through heating of the fuse wire, the free end of the strip will be blown through the said opening, and a readily torn disk interposed between, the inner side of the cap and the free end of the strip and normally closing the said opening,

In testimony whereof I afiix my signature.

FRANK n. KAISER. [us] 

